Raising the Bar: Increased Hydraulic Pressure Allows Unprecedented High Power Densities in Pressure-Retarded Osmosis

Journal Article · Tue Dec 31 23:00:00 EST 2013 · ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS

DOI:https://doi.org/10.1021/ez400117d· OSTI ID:1211144

Straub, AP; Yip, NY; Elimelech, M

Pressure-retarded osmosis (PRO) has the potential to generate sustainable energy from salinity gradients. PRO is typically considered for operation with river water and seawater, but a far greater energy of mixing can be harnessed from hypersaline solutions. This study investigates the power density that can be obtained in PRO from such concentrated solutions. Thin-film composite membranes with an embedded woven mesh were supported by tricot fabric feed spacers in a specially designed crossflow cell to maximize the operating pressure of the system, reaching a stable applied hydraulic pressure of 48 bar (700 psi) for more than 10 h. Operation at this increased hydraulic pressure allowed unprecedented power densities, up to 60 W/m(2) with a 3 M (180 g/L) NaCl draw solution. Experimental power densities demonstrate reasonable agreement with power densities modeled using measured membrane properties, indicating high-pressure operation does not drastically alter membrane performance. Our findings exhibit the promise of the generation of power from high-pressure PRO with concentrated solutions.

• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• DOE Contract Number: AR0000306
• OSTI ID: 1211144
• Journal Information: ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS, Journal Name: ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS Journal Issue: 1 Vol. 1; ISSN 2328-8930
• Country of Publication: United States
• Language: English